biology

Sopite syndrome

Sopite syndrome is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Sopite syndrome rather than just read about it. In short: The sopite syndrome (; from Latin sopire 'to put to sleep') is a neurological disorder that relates symptoms of fatigue, drowsiness, and mood changes to prolonged periods of motion. The sopite syndrome has been attributed to motion-induced drowsiness such as that experienced by a baby when rocked.

Key takeaways

Sopite syndrome belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Sopite syndrome to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Sopite syndrome from memory before moving on to harder problems.

Reference excerpt

The sopite syndrome (; from Latin sopire 'to put to sleep') is a neurological disorder that relates symptoms of fatigue, drowsiness, and mood changes to prolonged periods of motion. The sopite syndrome has been attributed to motion-induced drowsiness such as that experienced by a baby when rocked. Researchers Ashton Graybiel and James Knepton at the US Naval Aerospace Medical Research Laboratory first used the term "the sopite syndrome" in 1976, to refer to the sometimes sole manifestation of motion sickness, though other researchers have referred to it as "Sopite syndrome."

Signs and symptoms Several symptoms are associated with the sopite syndrome. Typical responses include:

drowsiness yawning disinclination for work lack of social participation mood changes apathy sleep disturbances other fatigue-related symptoms The sopite syndrome is distinguished from other manifestations of motion sickness (i.e. nausea, dizziness, etc.) in that it may occur before other symptoms of motion sickness or in their absence. The sopite syndrome may persist even after an individual has adapted to the other symptoms associated with motion-induced sickness.

Severity The effects of the sopite syndrome may range from minor physical inconveniences to hazardous conditions. People who operate automobiles, airplanes, etc., may experience impaired motor function due to the motions of the vehicle. These impairments often result in a decreased attention span; those who consider themselves well-rested may still succumb to drowsiness at inopportune moments. The sopite syndrome may therefore contribute to motor vehicle accidents in which automobile operators fall asleep at the wheel. However, the sopite syndrome itself does not directly result in death. A subject experiencing the sopite syndrome on a frequent basis may increase the number of hours spent sleeping by fifty percent. A study of motion sickness occurrences in workers on an offshore oil vessel showed a large majority of participants experienced mild symptoms of fatigue. Many participants also experienced severe sleep disturbances. These symptoms were associated with impaired task performance.

Causes The sopite syndrome has been associated with visually-induced and vestibular motion sickness. Other factors associated with drowsiness such as darkness or physical fatigue may intensify the effects of motion-induced sleepiness. The sopite syndrome may occur with little motional stimulus (though the greatest effects tend to be observed in subjects who have been exposed for longer periods of time), and often persists for a time after the motional stimulus has ceased.

Susceptibility A study of certain aspects of motion sickness among medical transport attendants showed that the onset of the sopite syndrome is likely to occur independently of the mode of transportation; little difference was observed in the frequency of sopite symptoms for ground transport compared to air transport. Also, the length of time exposed to vehicular motion did not appear to affect the occurrence (or lack thereof) or severity of the sopite syndrome. No difference was observed in the incidence of the sopite syndrome for men versus women. The sopite syndrome is likely a cumulative disorder. For instance, when a subject has the flu, a hangover may exacerbate the symptoms of the illness. A subject normally resistant to motion sickness may experience symptoms of motion sickness when also experiencing flu-like (or hangover-like) symptoms.

Mechanism The exact mechanism for the induction of the sopite syndrome is still unknown; however, a leading theory asserts that the sopite syndrome (and perhaps motion sickness in general) is somehow related to the reticular formation, an area of the brainstem associated with arousal. A study of motion-induced effects on the P50 potential (a measure of arousal) showed that subjects exposed to motion environments experience decreased sensory gating, which involves the filtering of information in the brain. In the case of Space Motion Sickness, the unweighting of otolith organs can lead to a sensory mismatch between the visual, vestibular, and somatosensory systems. Motion studies in which the subjects lacked vestibular systems did not experience symptoms of the sopite syndrome or other manifestations of motion sickness.

Vestibular system The role of the vestibular system in the inducement of the sopite syndrome or related symptoms may be difficult to ascertain. Researchers must compare the results of test subjects experiencing a motion environment to a control environment lacking motion. Experimental subjects who suffered increased fatigue in a rotating environment apparently recovered from this side effect when the same environment ceased motion. In similar studies, control subjects lacking vestibular function did not experience the motion-induced drowsiness associated with the sopite syndrome, while subjects with normal-functioning vestibular systems did experience increased fatigue in the rotating environments.

Visual stimulus The relation of the visual-vestibular stimulus to the sopite syndrome may be observed when comparing airline cockpit crew with cabin crew. While the former typically experience more confined conditions, the airline cabin crew tend to experience more symptoms associated with sopite syndrome; this effect may be attributed to the lack of visual validation and increased movement of the cabin crew.

Biochemicals Certain hormones or biochemicals likely affect the pathways associated with motion sickness in general and the sopite syndrome in particular. Studies reported by Kennedy, Drexler and Kennedy (2010) have investigated the role of cortisol and melatonin (a hormone associated with the maintenance of circadian rhythms) in motion-induced drowsiness. Subjects were exposed to vection-producing environments (virtual reality, for example) and symptoms were evaluated using a Simulator Sickness Questionnaire. Sopite symptoms were also measured using a developed scale. The levels of endogenous cortisol and melatonin were then compared with levels before the subjects were tested in the vection environments. Most subjects showed increased levels of endogenous cortisol and melatonin post-vection. Melatonin may therefore be involved in the drowsy state associated with the sopite syndrome.

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with Sopite syndrome

Start with the simplest possible case. Write down what Sopite syndrome claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Sopite syndrome before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Sopite syndrome ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Sopite syndrome

In research: Sopite syndrome appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Sopite syndrome in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Sopite syndrome is common in secondary-school and first-year university syllabi. It links to neighbouring topics Diseases of the ear and mastoid process, Neurological disorders, Syndromes, so understanding it makes those chapters shorter.
In everyday life: Look for Sopite syndrome outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Sopite syndrome in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Sopite syndrome means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Sopite syndrome out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Sopite syndrome in simple terms?

Why does Sopite syndrome matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Sopite syndrome?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Sopite syndrome.